Many modern pump systems are provided with various types of controls in order to control pump units in specific ways. Circulation pumps are often intended to deliver a specific head and flow rate at given circumstances in order to meet particular requirements. To meet the different requirements, the pump units may be controlled according to different control patterns by changing one or more drive parameters. This may done by the user of the pump by use of input means provided at the pump itself, e.g. via an interface, such as a touch screen, at the pump unit. However, providing a pump unit with a display or a touch screen adds costs to the production price of the pump unit and thus also to the purchase price of the end consumer. Further, it entails a security risk, if anybody can gain access to the control system and to control the system to drive the pump unit at erroneous drive conditions.
EP 1 321 912 discloses a pump unit with a control or regulating device for controlling or regulating a drive of the pump, wherein the device has a light source for emitting light, which can be used for the transmission of data to a reader device.
WO 2013/041616 discloses a pump unit having an electrical drive motor and a control device for controlling the drive motor.
WO 2013/117401 discloses an electric motor, which is provided with a signal device for indicating at least two different operating states. For this purpose, the signal device has six light-emitting diodes, which are connected to flash mutually offset in time from one another, when the motor is running, so that they represent the rotary motion of the motor.
While a simple diode display may provide a simple visual indication to a user, e.g. green light for correct operating conditions and red light for faulty operating conditions, it is difficult to extract more detailed information about the operating condition of the pump. Further, the pump unit is usually provided with an energy-saving switch-mode converter or power supply, and switch-mode noise may thus influence external instruments.